Compressed air coolant circulatory pump



v Feb. 5, 1946. I J. DE w, GRAY ETAL l 2,394,169

COMPRESSED AIR COOLANT GIRCULATGRY PUMP Filed .June 2e, 194s z 'sheets-sheetl BY M'Zffed fo/26,

wat.. avm Aguayo larly subject to wear.

Patented Feb. 5, 1946 John De Witt Gray and Wilfred S. Stone, Chlcago, Ill., assignors to John De Witt Gray and Lloyd L. Miller, Chicagolll., partners doing business as Gray-Miller Co. s

Application June 26, 1943, Serial No.'492,368

(Cl. S-238) 13 Claims.

This invention relates to coolant circulatory systems of the type described in the co-pending application Serial No. 436.082 of John De Witt Gray and Edward C. Rothacker. More particularly, this invention relates to such a coolant circulatory system driven by compressed air.

Heretofore, coolant pumps have commonly been driven by an electric motor. Electricity is always available in places employing machine tools. Electrically driven pumps, however, are particu- Whether the pump is of the gear or centrifugal type, metal chips will work their way down from the collection pans beneath the machine tools into the coolant reservoir and thence into. the pumps. Moreover,

-the coolant acquires considerable heat and very quickly raises the temperature of the pump and motor to a point where it loses eiiciency,

Broadly, the object of this invention is to provide a coolant circulatory system or pump driven by air pressure. In a large percentage of the machine shops or other places where machine tools are used, compressed air is as available as electricity. Compressed air is commonly used to blow chips from the work during machining operations.

Applicant uses compressed air for forcing iluid from a substantially gas-tight tank much in the way that air is now used to assist in evacuating a beer barrel. Unlike the problem of evacuating a plurality of beer barrels in succession, a'coolant circulatory system functions by means of returning the fluid or coolant from a collection pan beneath the machine tool by gravity to the original container or pumping means. In order to obtain continuous operation, the fluid must be reintroduced to the original container during a period when there is no compressed air therein. This necessitates the employment of more than one container. After the compressed air has emptied one container, it must almost instantaneously commence to empty a second container because the machine tool may be working on metal where lubrication and cooling must .be substantially continuous.

With the foregoing considerations in mind, one specific object of this invention is to employ a double tank arrangement wherein the air pressure will evacuate one tank while the other'tank is not under pressure but is receiving by gravity fluid from the coolant collection pan. In connecton with this object, applicant provides automatic means for alternately emptying one tank and then the other.

Another specic objec tof this invention is Vto provide means for'transferring the application of air pressure from one tank to the other tank almost instantaneously so that'a single delivery line from the unit will result in a steady ow at the nozzle of the circulatory system. In this connection, applicant uses a spring toggle arrangement controlled bya float in one of the chambers. A lever train controlling al1 of the valves for introducing compressed air, forY introducing by gravitycoolant from the collection pans. and for alternately opening and closing the coolant delivery lines from the two chambers is controlled l.by the action of a spring which isfree to snap into either of two positions depending upon the position of the float in one of the chambers.

The invention includes many structural features. It is desirable that coolant pumps be inexpensively made. Toward that end applicant employs a small round container of standard construction positionable in a larger container, likewise -round and of standard construction. The smaller container is mounted removably on the under side of a lid for the large container. Mounted on the upper side of the lid and straddlingrthe side wall of the smaller container is the valve assembly which is built into a single casting. All of the movable parts of the device are mounted on the lid, with the result that the device may be readily disassembled. The opening and closing of the valves is controlled entirely by a float, which gives a positive action although not requiring iinely machined bearings and journals in the linkage connections.

These and suchA other objects as may hereinafter appear are attained in the embodiment of the invention shown in the accompanying drawings wherein: y

Figure l is a side view in section of the device; Figure 2 is a plan View taken on the line 2-2 of Figure l; and

Figure 3 isa plan view taken on the line 3--3 of Figure 1.

Continuing to follow the drawings, the numeral IIJ identiiies a largecontainer or chamber having a bottom I2 and a strong lid. Ill.l A gas-tight connection between the container I0 and the lid I4 may be obtained by employing a gasket I6 and suitable fastening means such as the nuts and bolts I8. Suspended from the lid I4 is a second container 20 havinga bottom 22 and using the lid I4 as a top yclosurefmember. Here-again a gas-tight connection is obtained byV means of a gasket 24 and suitabel fastening means 26.

Mounted on the top of the lid I4 is a casting 28 having a coolant collection bowl `30 and through its base substantially horizontal or parallel to the lid I4 a cylindrical chamber 32 open at one end. Two passageways or delivery ports 34 and 36 in the bottom of the bowl 30 open directly into the cylindrical chamber 32 and extending through the lower sidewall of the cylindrical chamber-132 as passages 3.8 and 4|), these passages being defined by integral depending collars 42 and 44. These collars 42 and 44 are eX- teriorly threaded at 46.

From the cylindrical chamber 32, downwardly directed, are passages 48 and 50 through which The siX depending Acollars 42, 44, 52, 54, 51 and 59 constitute the means for assembling the casting 28 in an air-tight relationship to the lid I4. A gasket such as 60 is positioned over cach collar and a nut such as 62 is tightened over each of the collars after the casting 28 has been seated in siX holes cut in the lid I4 in registry with the depending collars.

Two delivery tubes 62 and 64 having their upper ends threaded are screwed into the internal threads in the bases of the depending collars 51 and 59.

Referring now to Figure 3, the upper end of the delivery passageways 56 and 58 turn at right angles and leave the casting horizontally by the passageways 66 and 68 into pipes 10 and 12. The two pipes or delivery lines join to form a single delivery line 14, there being a check valve 16 in the pipe 10 and a similar check valve 18 in the pipe 12.

Leading horizontally into the cylindrical cham-.- ber 32, referring to Figure 3, is a passageway 80 f or introducing compressed air yfrom the line 82. Also leading into cylindrical chamber 32 are horizontal air vents 84 and 86. Disposed in the cylindrical chamber 32 is a piston 88 which has its cylindrical surface cut back between end portions 90 and 92 to form between partitions 94 and 96 with the Walls of the` cylindrical chamber 32 a plurality of movable chambers which bear a xed relationship to each other and which are in communication with various passageways leading from the cylindrical chamber32, depending upon the position of the piston 88. Threaded into the end portion 92 of the piston 88 is a rod or link 98 which passes through an opening in an end plate 99 which closes the open end of the cylindrical chamber 32 and which is held in position by cap screws such as |00.

Referring now to Figure 1, the outer end of the rod 98 is.bent and rides in a slot |02 of a bell crank lever |04 pivotally mounted at |06 on an extension |08 of the casting 28. At lts outer side, the bell crank lever |04 carries a closed track in which rides the turned end ||2 of a link ||4 which passes through an opening ||6 inthe lid I4. In order to hold the link I4 closely to vertical movements, or a movement at right angles to the lid |4,1a reinforcing member ||8 is suitably fastened to the bottom of the lid 4 and ing member and the link 4 held in position by a cap screw |22.

The lower end of the link ||4 rides in a closed track |26 in an arm |28 pivoted at |30 to a depending support member |32. The support member |32 is a casting which is held in assembled relationship with the lid. i4 by means of an opening' |34 Vin the support r`member |32 tting over the enlarged collar 44 and a nut |36 which is drawn up on the external threads on the col lar 44..

Pivotally connected to the arm |28 at |38 is another link |40 having a closed track |42 in its lower end in which track rides a stud |44 which is formed in tegrally with a T-shaped casting |46. The T-.s'haped casting |46 is pivotally mounted at |48 on an extension |50 0f the casuing |32 .inwardly directed with respect to the inside wall of the container 20. The T-shaped casting therefore can move in an arc around the center |48 from the continuous line position illustrated to the broken line position |52. As .may be seen by comparing Figure 2 with Figure l, the depending link |40 is mounted behind the T-shaped casting |46, the relationship being maintained by a nut |53 which loosely engages the side walls of the link |40.

Projecting forwardly of the T-shaped casting |46 as viewedin Figure 1 are two lugs |54 and 56 mounted at the outer ends of the cross Vmember of the T respectively. Between these lugs |54 and |56 is positioned the arm |58 .of a oat |60 which arm is pivotally mounted at |62 on an outwardly directed extension |64 of the support member |32. Referring .to Figure 2, it will be noted that the arm |58, in order to move vertically and at all times engage either one or the other of .the lugs |54 and |56, .must .be spaced from the support member |32 and this is eiected by means of the spacer member |66 which is fastened to the portion |64 by any suitable means. Connecting the spacer member |66 to the intersection point |62 of the T-shaped casting is a spring 61. Referring to Figure 1, it is evident that the T-shaped casting |46 will always assume one of two positions depending upon the relationship of the spring |61 to the pivotal point |48. If the .spring 61 is .above the pivotal point |48, the spring |61 will snap the T-shaped casting |46 into position |52, and .if the spring |61 is below thel pivotal point |46, it will snap the T-shaped member |46 into the continuous .line position shown.

The downwardly ydisplaced portion |66 in the arm |58 is to assure noninterference between the bulb in its uppermost position andthe link there may be packing |20 between the reinforc- 75 Continuing to referto Figure l, the line 14 is normally iiexible and terminates in the nozzle |68 which will be directed upon some machine tool such as |10.V Discharged iiuid vwill be collected in a pan |12 from which it will ow by gravity down the line |14 through a lid |16 into the collection :bowl 30. An air vent |18 is provided in the lid 16 of the collection bowl 30 which is tightly fastened thereto by cap screws such as forreasons hereinafter explained. A sieve |82 removably suspended from the under side of the lid |16 will .collect anylarge particles that may pass down the line |14.

From a .construction standpoint, the control mechanism functioning in the container 20 possesses the desirable characteristics of positive action, long life, and a minimum labor require- .ment in .fittingand aligning the operable parts.

None of the journals or bearings of the oat and linkage mechanism are machined, with the exception of the link I |4 and the opening through the reinforcing member ||8. Gaskets are relied upon to obtain the necessary seal between the inside of the containers and the outside.

Operation When the device is first made ready for use, the operable parts will be in the various positions vindicated by the continuous lines shown in Figure l.; The float |60 will be near the bottom of the container because there is no fluid in the system. The intake lines 82 and 80 for the compressed air may be connected to a source of compressed alr but a control valve |84 will be maintained in closed position. The collection bowl 30 may be connected by a line such as |14 to a collection bowl 36 by'permitting it to ow down the line |14 or the machine may be filled by pouring fluid directly into the collection bowl 30 through the opening |15. The coolant will flow down the passageways 36 and 40 into the container 20 and the iloat will begin to rise. 4 When the fioat reaches the dotted line position |88, the arm |58 will engage the lug |54 of the T-shaped casting |46. As the float |60 continues to rise, the T-shaped casting |46 will move counter-clockwise around the center |48. In so doing it is obliged to expand the spring |61. The movement of the T-shaped casting |46 does not raise the link |40 because the stud |44 moves freely in the closed track |43, although the stud does swing the link |40 inwardly of the container 20 around the center |36. When the float |60 reaches position |90, the stud |44, the point |48 and the point |62 will all be in alignment and the spring |61 will be stretched to the maximum extent permitted by the assembly. As the float |60 continues to rise under the influence of the incoming coolant, the spring |61 will assume control of the movement of the T-shaped casting |46 and snap it into position |52. In so doing the link |40 will be snapped upwardly and the bell crank lever |04 will be snapped into position |92. The float |60 may continue to rise a short distance, but when the bell crank lever moves into position |92, the influx of coolant from the collection bowl 30 ceases and the passageway 50 which had been in communication with the vent 86 vcomes into communication with the compressed air intake line 80.

When this condition occurs, the valve |84, see Figure 3, is opened by hand and compressed air now passes down the passageway 80 through the chamber established by the partitions 94 and 96 of the piston 88, down the passageway 50, see Figure 1, into the container 20. The air pressure established in the container20 forces the fluid out through the delivery line 64 and ultimately to the tool |10. The rate of flow will It is also necessary for the flow ofcoolant to be continuous at a substantially constant pressur'e regardless of which tank, or 20, is being emptied without necessitating adjustment of the air pressure. For this reason the cross sectional area of the inside of the tank |0 is exactly twice the cross section of the outside dimensions of the tank 20. Inother words, the surface of oil engaged by the compressed air in the tank l0 is exactly equal in area to the surface of oil engaged by the compressedair in the tank 20.

Resuming the description of the operation, the coolant Ais now owing from the container 20 to the nozzle |68 and the container lil is being lled through the passageways 34 and 38, there being a vent to atmosphere through the passageway 48, cylindrical chamber 32 and air vent 84.` The chamber l0 will fill comparatively quickly due to the size of the openings 34 and 38 and in starting the device for the flrst time, the coolant shouldbe led into the collection bowlslowly so that the container i0 does not flood. If this should hapf pen, the fluid will flow up the passageway 40 and out through the air vent 84. Moreover, when the piston is again thrown to th'e position shown in Figure 1, the inflow of compressed air will cause quite a lot of trouble. The lid |16 is seeurely fastened to the top of the collection bowl 30 because when the position of the valve assembly is reversed, the air will vent to a certain extent up the passageways 34 or 36 Vand would splash out coolant in the collection bowl 3i) but for the tightly fastened lid |16 with its small vent |18.

As the float |60 descends withv the fluid level in the container 20, it ultimately reaches a position where it permits the spring |64 to throw the T-shaped casting from dotted line position |52 into the continuous line position shown. When this occurs, the bell crank lever |04 is snapped Vinto the continuous line position shown and the the system contains an adequate supply of fluid depend upon many .factors including the relationship of the surface area of the uid to the inside diameter of the delivery line 64 and to the control nozzle |68. The most important control in the rate of flow will be the air pressure in the tank 20. It is necessary to be able to control the air -pressure in order to adjust it for coolants of connection with the operation of this device as a whole. l

and an adequate supply of compressed air.

Attention is invited to the fact that the delivery lines 66 and 68, see Figure 3, each contain check valves to prevent the device from pumping fluid from one container into the other container. These valves are conventional and are shown schematically only.

Having thus descried our invention, what we claim as new and desire to claim by United States Letters Patent is: Y

1. A compressed air pump comprising means for collecting fluid not under pressure, a` container, a communicating means between said collecting means and said container, means for withdrawing a portion of said fluid from said container and having a delivery means, and means operated by air pressure for forcing the withdrawn uid through said delivery means, a common valve means in said communicatingrrneans and said delivery means, and a iioat means in said container and connected to said common valve means.

2. A compressed air pump comprising means for collecting fluid not under pressure, a substantially gas-tight chamber, means including a communicating means i between said collecting means and 4said chamber for introducing fa' portion ofpsaicl :duid into said chamber, a delivery means having an outlet in the lower part of :said chamber, and a common valve means in :said communicating means and said delivery means operable when the kaforesaid introducing means is not functioning ior introducing compressed air to the .chamber where-by fluid flows into the outlet.

`3. A compressed air pump comprising means for collecting fluid not under pressure, a substantially gas-tight chamber including a communicatingmeans between said connecting means and said chamber. valve means in vsaid communicating means for introducing a portion of said fluid into said chamber, a `delivery means having an ,outlet in the lower :part .of said chamber, a sec- .ond avalve means in :said delivery .means and operable when the aforesaid introducing means is not functioning -for introducing compressed .air to the chamber whereby uid flows into the outlet, a .second substantially gas-tight chamber having asimilar set of valves, and means for functioning the valves for the two chambers in opposed sequence whereby when one chamber is being emptied of uid by the compressed air, the other chamber is being iilled from the collection means.

4. A compressed air pump comprising means for collecting fluid not under pressure, a pair of substantially gas-tight containers, and two-position valve means capable in one position of rilling `one container with uid from the collecting means while concurrently connecting the other container to -a source of compressed air and capa- -ble in vits second position .of filling the other container with fluid `from the collecting means While concurrently connecting the first container to a source of compressed air, and means responsive to the fluid level in one of the containers for fully actuating said two-position valve into either of Vits positions. l

5. A compressed air pump comprising a pair of substantially gas-tight containers, common valve means for controlling the introducing of fluid by gravity to one container and compressed air to the other container, means for moving said valve means to control the reversing of said air and uid connections whereby the compressed air is introduced to the iirst container, fluid is introduced to the second container, and float means in the first container for functioning said reversing means when the v:duid level in the first container reaches a predetermined level, and means responsive to a selected position of said iioat means for fully actuating said moving means irrespective of further movement of .the float means in the samedirection.

6.A compressed air pump comprising means for collecting fluid not under pressure, a pair of substantially gas-tight containers having equal horizontal cross sectional areas, .valve means for alternately connecting the collecting means to one container and a source of compressed air to the other container, a oat in one container functioning said valve means when in an upper or lower position, and means responsive to a selected position of said oat means for fully actuating said moving means irrespective of further movement of the float means in the same direction.

7. A compressed air pump comprising means for collecting fluid not under pressure, `a pair of substantially gas-tight containers, a two-position valve capable in one position :of connecting .the iirst container yto the collection ,means and the second .container to a source of vcompressed air and capable in the second position of reversing the connections so that the second container is `connected with the fluid collection vmeans and the first container is connected .to the source voi? compressed air, and means ior holding said valve in the rst position until the iirst container is comparatively full of liuid and of automatically shifting the valve to the second position when the lrst container becomes comparatively empty.

8. A compressed air pump .comprising means -for'collecting uid not under pressure, a pair of substantially gas-tight containers, a two-position valve capable in .one position of connecting the rst container to the collection means and the second container to a .source .of compressed air .and capable in the second position of reversing the connections so that the second .container is connected with the fluid collection means and .the rst container is connected to the source of compressed air, `and means for holding said valve in the rst position until the first container is comparatively full of fluid and .of automatically sluiting the valve to the second position when the rst container becomes comparatively empty.

9. A compressed air pump comprising means for collecting uid not under pressure, a pair of substantially gas-tight containers, a two-position valve ,capable in one position of connecting .the rst container to the collection means and the second container to a source of compressed air and capable in the second position of reversing the connections so that the second container is .connected with the fluid collection means and the first container is connected to the source of compressed air, and a float in the first container so connected to the two-position valve that when the float is in a low position it will hold the valve in its first position and whenfthe oat is raised 40 it Will hold the valve in its second position.

10. A compressed air pump comprising means for collecting fluid'not under pressure, a pair of substantially gas-tight containers, a two-position valve capable in the first position of connecting the first container to the collection means and the second container to a source of compressed air and in the second position of reversing the connection to connect the second container tothe collection means and the iirst containerto the compressed air, and means responsive to the fluid level in the first container for practically instantaneously snapping said twoposition valve from one position to the other.

11. A compressed air pump comprising means for collecting fluid not under pressure, a` pair of substantially gas-tight containers, a two-position valve capable in the iirst position of connecting the rst container to the collection means and the second container to a source of compressed air and in the second position of reversing the connection to connect the second container to the collection means and the rst conv tainer to the compressed air, and means responsive to the fluid level in the nrst container Vfor practically instantaneously snapping said twoposition valve from one position to the other, said means comprising a spring operable upon the two-position valve only when it has passed a dead center point after which it is free to contract.

l2. A compressed air pump comprising a pair of substantially gas-tight containers, a two-position valve capable in one position of introducing compressed air to one container and fluid to the other container and in the second position of retainers being substantially equal, a two-position valve capable of introducing uid to one container and compressed air to the other container when in its first position and of reversing the air and gas connections when in its second position, and float means within one container for snapping the valve from the rst position to the second position in order to produce a continuous ow of fluid out a delivery line.

JOI-IN DE WI'I'I GRAY. WILFRAED S. STONE. 

